Industrial overhead roll-up doors typically permit and prohibit access to openings or doorways. These doors typically include a door panel having opposing side edges that engage with, and are vertically guided in, side columns. In some environments it may be necessary to provide the door panel with an increased wind load resistance in order to prevent the door panel from disengaging from the side columns, particularly when the door panel is moving vertically. In order to enhance the door's resistance to high winds and/or air pressure, it may be desirable to manufacture the door panels using flexible, heavy duty materials having an increased weight in order to provide better wind load resistance to the door panels. Regardless of wind load, it may be desirable to utilize door panels made from such heavy duty materials in industrial applications in order to provide a stronger door panel more resistant to damage, and/or a door panel capable of providing a better, more impenetrable barrier between sides of the opening.
Examples of heavy duty materials known in the art for use in such situations include Styrene-Butadiene-Rubber (“SBR”) and ethylene propylene diene Monomer rubber (“EPDM”). While such materials may be used to create overhead roll-up doors, SBR, EPDM, and other similar materials are generally not made in custom widths. Typically, panels made from these materials are not wide and/or long enough to cover many openings or doorways opened and blocked by overhead roll-up doors in industrial applications.
In order to provide a large enough door panel, it is known in the art to connect multiple SBR, EPDM, or other heavy duty material panels together to form one large door. In practice, the multiple panels are typically joined by “skiving” the panels together. In order to skive the panels together, the edges of each material panel that are to be joined are cut at very sharp mating angles that are configured to overlap each other. The overlapped edges are then glued together. Skiving, however, has some drawbacks.
One drawback to creating a door panel by skiving together multiple material panels is the expense and precision of the equipment. In order to provide a smooth cut on each material panel and insure a proper mating angle, each cut must be extremely precise. In order to insure this precision, skiving blades typically need to be replaced frequently, increasing the manufacturing cost of the door panels.
Skiving may also produce significant waste. Each material panel must have a sufficient amount of material removed there from in order to insure a proper and satisfactory overlap for adhering each adjacent panel in a manner capable of supporting the remainder of the door panel.
Because of the overlap between each panel, skiving may also require use of additional material. Inasmuch as each material panel is cut and overlapped with another, over large expanses the total overlap may require the use of additional material panels to fully block the opening.
The overlap may also lead to uneven rolling of the door panel in the partially or fully open position. Uneven rolling may lead to buckling in the door panel when rolled up or may lead to increased roll sizes which requires larger headers, thereby increasing the cost of the header while reducing the size of the opening.
Another drawback to skiving is that it increases the tension on each material panel in the overall door as the skived joints make each panel located above the joint bear a significant portion of the weight of each panel located below the joint. In many environments it may be desirable to provide a window or a clear panel permitting vision from one side of the door to the other when the door panel is closed. If, for example, a clear polyvinyl chloride (“PVC”) panel is used with a door panel that is skived, the PVC panel will typically stretch and deform from carrying the weight of the skived material panels located below the PVC panel. Since the skived door panel relies on the overlap seams to lift the panels below as the door panel moves vertically upwards, less strong materials like PVC, will stretch and deform, creating problems in the door panel and perhaps eliminating some or all of the visibility through the clear section. In order to avoid stretching and door panel damage, it is known in the art to cut a hole or area out of a full door panel and replace it with a clear material—however doing so limits visibility through the door panel. Furthermore, environments with many door panels, particularly when the door panels are constructed of black materials and/or the environment is poorly lit, limited visibility may be hazardous to the door and any people and objects attempting to pass there through.
An alternative method of joining panels together is shown in U.S. Pat. No. 4,736,785 to Seuster (“the '785 patent”). As shown in the '785 patent, it has been contemplated that panels may be horizontally butt jointed together with the horizontal butt joints secured with profiled stabilizing members held together by screws. However, amongst the problems associated with only horizontal support, utilizing profiled stabilizing members may lead to uneven rolling in the open position, and the '785 patent provides no vertical support for any of the panels, thereby leaving substantial weight bearing responsibilities on each panel for the panels below, and, in turn, the possibility that particular panels or materials may stretch or deform. Having no vertical stabilizing members or similar structure may also lead to increased wear on each panel forming the door taught in the '785 patent as there are no vertical strips or structures for the door panel to roll up on, leaving the faces of each door panel to contact each other.
Therefore, it would be advantageous to have a door panel utilizing heavy duty materials without requiring that multiple panels be skived together.
It would be further advantageous if such a door panel was capable of incorporating at least one full width panel made from a material different from the remainder of the material panels.
The present invention is directed to solving these and other problems.